> To get the behavior you're describing,
> there would have to be some way for Majordomo to construct some "super
> list" on the fly, cull the duplicate addresses, and send it to that.
> Very difficult to do, especially since you might get a separate
> _incoming_ copy of the message for each list.
In fact, I do exactly this, but Brent is right in what he implies here,
which is that this has to be done outside of majordomo. We have a bunch
of machine-status lists here so that users can be informed when a system
goes down or is planned to be taken down. We have a "master status list"
which we want to consist of everyone who is on any of the other status
lists, for things like room power outages that affect all systems.
What we essentially do is have the real alias invoke another script
that runs all the majordomo machine-status list files through "sort | uniq"
(to eliminate duplicates) and builds another majordomo list file on
the fly, then sends the message to this "new" majordomo list. This
has exactly the desired effect of giving each user who is on any of
the status lists exactly one copy of the message. Further, we restrict
subscriptions to the status lists to firstname.lastname@example.org addresses, so we
can be certain that no user can be subscribed to different lists with
a different address. This extra restriction required hacks to majordomo,
but really this was the main reason we chose majordomo over other list
management packages. Being a perl script, it is relatively easy to
make necessary local changes like that.